Dual gluing filter

ABSTRACT

A fluid treating filter arrangement including a filter frame enclosing two retaining screens with filter media disposed therebetween, at least one of the retaining screens being attached to the frame by two types of adhesives, the adhesives utilized being a fast setting and a slow setting adhesive.

United States Patent 1 Jackson July 24, 1973 1 DUAL GLUING FILTER [76],Inventor: Robert L. Jackson, Louisville, Ky.

[22] Filed: Sept. 27, 1971 [21] Appl. No.: 183,789

[52] US. Cl 210/495, 55/514;5l8, 55/DIG. 31, l56/291;309 [51] Int. Cl.B01d 27/08 [58] Field of Search 55/DIG. 31, 514, 55/518; 156/309,291210/495 [56] References Cited UNITED STATES PATENTS 2,715,453 8/1955Lange 55/DIG. 31 2,929,544 3/1960 Herschler 156/291 2,965,197 12/1960Dow et al. 55/514 2,975,091 3/1961 Tobey 3,003,581 10/1961 Greason....

3,313,218 4/1967 Nichol l56/309 Primary Examiner-Bernard Nozick AttorneyRalph Bv Brick, Charles G. Lamb et a1.

[57] ABSTRACT A fluid treating filter arrangement including a filterframe enclosing two retaining screens with filter media disposedtherebetween, at least one of the retaining screens being attached tothe frame by two types of adhesives, the adhesives utilized being a fastsetting and a slow setting adhesive.

6 Claims, 2 Drawing Figures DUAL GLUING FILTER BACKGROUND OF THEINVENTION The present invention relates to a fluid treating filter. Itis particularly concerned with the use of two types of adhesives in thepreparation of fluid treating filters. More particularly, it relates toan improved fluid treating filter utilizing a fast setting adhesive anda slow set ting adhesive in bonding filter media retaining screens to afilter frame.

In preparation of fluid treating filters of the type which are preparedby inserting a fibrous material, such as a fibrous glass filter mat,between two perforated retaining sheets of metal, such as bottle capresidue, and then holding the perforated sheets together by an inwardlyfacing U-channel constructed chipboard filter frame, adhesives which setup quickly and are exposed to a range of temperatures from -lF to 140Fand are capable of withstanding shock occurring from warehouse handlingand operation in a fluid stream are necessary. However, presently in thepreparation of filters of the aforementioned type, a single adhesivewhich accomplishes the aforementioned and is feasible, economically, hasnot been found. That is, adhesives which set up quickly, are effectiveover a wide temperature range, and which withstand shock in handling andoperating conditions have not been found. The adhesives that arepresently in use generally solve the problem of quick setting but havenot been found to be dependable over the aforementioned temperaturerange or to withstand shock occurring from handling and operatingconditions. The presently used fast setting adhesives generally are ofthe hot melt type. That is, they are applied while hot and upon chillingharden to form a bond between the dissimilar materials. The maximum bonddeveloped between a chipboard filter frame, the most common type offilter frame, and the metal retaining screens is generally in the roomtemperature range as this is the temperature to which most of thesefilters are exposed. However, it has been found that during extremelylow temperatures, handling in warehouses, shipping, and the like, theseshocks shatter the adhesive lines. Furthermore, elevated temperaturesresult in the adhesive line opening as the adhesive becomes soft andpliable. Thus, adhesiveswhich are economically feasible for usage in thepreparation of the aforementioned filters and which will be both fastsetting and yet durable over a wide temperature range while at the sametime preventing the chipboard frame from separating from the retainingscreen under handling or operating conditions has been widely sought.

SUMMARY OF THE INVENTION In the present invention, it is recognized thatit is desirable to provide an adhesive for joining a filter frame to ametal retaining screen wherein the adhesive acts quickly to join theframe to the screen and yet is durable over a wide temperature range andunder strenuous operating conditions. Furthermore, it is recognized thatit is desirable to provide economical adhering means with increasedstructural strength characteristics.

The present invention advantageously provides a straightforwardarrangement for the preparation of a fluid treating filter havingsuperior bonding properties at the overlapping juncture of the retainingscreen and the filter frame. The present invention further provides forthe preparation of a filter which utilizes a fast setting adhesive and aslow setting adhesive, the fast setting adhesive bonding the filterframe with filter media retaining screens for assembly and packagingwhile maintaining this bond until the slow setting adhesive develops itsbond, the slow setting adhesive having strong structural characteristicsand permanent bonding under strenuous handling and operating conditionsover a wide temperature range. The present invention even furtherprovides for the preparation of a filter requiring less fast settingadhesive than heretofore used.

It has been found that by preparing a filter utilizing a fast settingadhesive and a slow setting adhesive the bonding characteristics offilter media metal retaining screens with a filter frame have beengreatly improved. Furthermore, with the adhesives, as hereinafterdescribed, the problem of the filter frame loosening from the metalretaining screens in operation of the fluid treating filter has beenvirtually eliminated. Also, it has been found that by using a slowsetting adhesive with a fast setting adhesive, the economics of the useof the slow setting adhesive is more than offset by the reduction of theamount of fast setting adhesive used.

Various other features of the present invention will become obvious tothose skilled in the art upon reading the disclosure set forthhereinafter.

More particularly, the present invention provides a fluid treatingfilter comprising a filterframe and at least two retaining screens, withfilter media disposed therebetween, the retaining screens being inparallel and having edges in communicative relation with the filterframe; and a fast setting adhesive and a slow setting adhesive beingdisposed at the juncture of at least one of the retaining screens withthe filter frame whereby the fast and the slow setting adhesives attachthe filter frame to the retaining screen.

It is to be understood that the description of the example of thepresent invention given hereinafter is not by way of limitation andvarious modifications within the scope of the present invention willoccur to those skilled in the art upon reading the disclosure set forthhereinafter.

Referring to the drawings:

FIG. 1 is an exploded perspective view of a filter of the presentinvention; and

FIG. 2 is a perspective view of the filter of FIG. 1.

As can be seen in FIG. 1 of the drawing, the fluid treating filter ofthe present invention includes retaining screens 2a and 2b having aplurality of flow-through apertures 6a and 6b, respectively, disposedtherein, with filter media 1 disposed therebetween. Opposed channelshaped ends 3a and 3b (FIG. 2) and opposed channel shaped sides 4a and4b make up the filter frame 9 (FIG. 2) which surround and enclose theretaining screens 2a and 2b with the filter media I disposedtherebetween.

Channel shaped end 3a includes two opposed leg portions lla and 11b, anda base portion Ilc disposed therebetween, legs 11a and 11b having ontheir inner faces fast setting adhesives 7a and 7b, respectively, andslow setting adhesives 8a and 8b, respectively, attached thereto foradhering end 3a to coextensive edges of screens 2a and 2b. Fast settingadhesives 7a and 7b are added in strips to the inner faces of legs Ilaand 11b generally adjacent the juncture of legs 11a and 11b with base11c whereas the slow setting adhesive 8a and 8b are added in strips tothe inner faces of legs Illa and llb generally along the extreme edge ofthe legs lla and 11b. The addition of the slow setting adhesives 8a and8b along the edge of the legs 11a and 11b generally yields a better bondbetween the end 3a and the retaining screens 2a and 2b as there is lessbending moment in the interior of the filter than around the edges.

Channel shaped side 4a includes two opposed leg portions 12a and 12b,and a base portion 12c disposed therebetween, legs 12a and 12b having ontheir inner faces fast setting adhesives 7c and 7d, respectively, andslow setting adhesives 8c and 8d, respectively, attached thereto foradhering side 4a to coextensive edges of screens 2a and 2b.

Opposing channel shaped end 3b and opposing channel shaped side 4b arealso provided with fast and slow setting adhesive (not shown) on theinner faces of inwardly extending legs in the same manner as describedabove for the end 3a and side 4a.

The fast setting adhesives utilized in the present invention are thoseknown as hot melts, hot melts being the term applied to thosethermoplastic adhesives that flow at elevated temperatures, such as350F, but upon chilling harden and become tacky. These include, forexample, hide glues, bone glues, polyethylene base binders,polypropylene base binders, ethylene vinyl acetate binders, and thelike.

The slow setting adhesives used in the present invention are those knownas cold adhesives, cold adhesives being the term applied to thoseadhesives that are applied at room temperature and after a period oftime develop adhesive properties. These include solvent dispersion andemulsion type adhesives having glue lines that do not open up or shatterin a temperature range of from about lF to about 140F. The solventdispersion and emulsion type adhesives include adhesives from bases,such as synthetic rubber, natural rubber, polyvinyl acetate, and thelike.

In the preparation of fluid treating filters of the present invention,fibrous material 1 of low density and permeability, such as glassfibrous material, is placed between metal retaining screens 2a and 2b.Hot-melt or fast setting adhesive 7 and cold or slow setting adhesive 8are applied to the inner faces of the legs extending from the channelends 3 and sides 4 in strips at the positions mentioned previously. Thelegs of ends 3 and sides 4 are then placed in overlapping relationshipwith coextensive edges of screens 2a and 2b completely enclosing theretaining screens 2a and 2b with the filter media 1 disposedtherebetween. Pressure is applied to the outer faces of the legs of thechannel shaped ends 3 and sides 4 for a period sufficient to allow thehot melt adhesive 7 to chill and adhere to the edges of the retainingscreens 2a and 2b. The fast setting or hot melt adhesive insures theholding of the channel shaped filter frame ends 3 and sides 4 inadhering relationship with the retaining screens 2a and 2b until thecold or slow setting adhesive develops its bond.

It will be realized that various changes may be made to specificembodiments shown and described without departing from the principlesand spirit of the invention.

What I claim is:

l. A fluid treating filter comprising a filter frame and at least tworetaining screens with filter media disposed therebetween, saidretaining screens being parallel and having edge portions in contactrelation with said filter frame; and a fast setting adhesive having anadhesive base selected from the group consisting of bone glues, hideglues, polyethylene base, polypropylene base, and ethlene vinyl acetateand a slow setting adhesive having an adhesive base selected from thegroup consisting of synthetic rubber, natural rubber, and polyvinylacetate disposed in seperate portions between said retaining screenswith said filter frame edge portions whereby said fast and said slowsetting adhesive attach said filter frame to said retaining screens.

2. The filter of claim 1 wherein said filter frame includes two channelshaped sides and two channel shaped ends.

3. The filter of claim 2 wherein each of said channel shaped sides andends includes two opposing leg portions and a base portion disposedtherebetween.

4. The filter of claim 3, said fast setting adhesive being attached tothe inner faces of said legs adjacent the juncture of said legs and saidbase, and said slow setting adhesive being attached to the inner facesof said legs at the extremity of said legs in attaching said sides andends in overlapping relationship with said retaining screens.

5. The filter of claim 4 wherein said retaining screens are of bottlecap residue.

6. The filter of claim 4 wherein said channel shaped sides and ends arechipboard.

1. A fluid treating filter comprising a filter frame and at least tworetaining screens with filter media disposed therebetween, saidretaining screens being parallel and having edge portions in contactrelation with said filter frame; and a fast setting adhesive having anadhesive base selected from the group consisting of bone glues, hideglues, polyethylene base, polypropylene base, and ethlene vinyl acetateand a slow setting adhesive having an adhesive base selected from thegroup consisting of synthetic rubber, natural rubber, and polyvinylacetate disposed in seperate portions between said retaining sCreenswith said filter frame edge portions whereby said fast and said slowsetting adhesive attach said filter frame to said retaining screens. 2.The filter of claim 1 wherein said filter frame includes two channelshaped sides and two channel shaped ends.
 3. The filter of claim 2wherein each of said channel shaped sides and ends includes two opposingleg portions and a base portion disposed therebetween.
 4. The filter ofclaim 3, said fast setting adhesive being attached to the inner faces ofsaid legs adjacent the juncture of said legs and said base, and saidslow setting adhesive being attached to the inner faces of said legs atthe extremity of said legs in attaching said sides and ends inoverlapping relationship with said retaining screens.
 5. The filter ofclaim 4 wherein said retaining screens are of bottle cap residue.
 6. Thefilter of claim 4 wherein said channel shaped sides and ends arechipboard.